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/*
* libwebsockets - small server side websockets and web server implementation
*
* Copyright (C) 2010 - 2018 Andy Green <andy@warmcat.com>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation:
* version 2.1 of the License.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301 USA
*
* included from libwebsockets.h
*/
/*! \defgroup generic AES
* ## Generic AES related functions
*
* Lws provides generic AES functions that abstract the ones
* provided by whatever tls library you are linking against.
*
* It lets you use the same code if you build against mbedtls or OpenSSL
* for example.
*/
///@{
#if defined(LWS_WITH_MBEDTLS)
#include <mbedtls/aes.h>
#include <mbedtls/gcm.h>
#endif
enum enum_aes_modes {
LWS_GAESM_CBC,
LWS_GAESM_CFB128,
LWS_GAESM_CFB8,
LWS_GAESM_CTR,
LWS_GAESM_ECB,
LWS_GAESM_OFB,
LWS_GAESM_XTS, /* care... requires double-length key */
LWS_GAESM_GCM,
LWS_GAESM_KW,
};
enum enum_aes_operation {
LWS_GAESO_ENC,
LWS_GAESO_DEC
};
enum enum_aes_padding {
LWS_GAESP_NO_PADDING,
LWS_GAESP_WITH_PADDING
};
/* include/libwebsockets/lws-jwk.h must be included before this */
#define LWS_AES_BLOCKSIZE 128
struct lws_genaes_ctx {
#if defined(LWS_WITH_MBEDTLS)
union {
mbedtls_aes_context ctx;
#if defined(MBEDTLS_CIPHER_MODE_XTS)
mbedtls_aes_xts_context ctx_xts;
#endif
mbedtls_gcm_context ctx_gcm;
} u;
#else
EVP_CIPHER_CTX *ctx;
const EVP_CIPHER *cipher;
ENGINE *engine;
char init;
#endif
unsigned char tag[16];
struct lws_gencrypto_keyelem *k;
enum enum_aes_operation op;
enum enum_aes_modes mode;
enum enum_aes_padding padding;
int taglen;
char underway;
};
/** lws_genaes_create() - Create RSA public decrypt context
*
* \param ctx: your struct lws_genaes_ctx
* \param op: LWS_GAESO_ENC or LWS_GAESO_DEC
* \param mode: one of LWS_GAESM_
* \param el: struct prepared with key element data
* \param padding: 0 = no padding, 1 = padding
* \param engine: if openssl engine used, pass the pointer here
*
* Creates an RSA context with a public key associated with it, formed from
* the key elements in \p el.
*
* Returns 0 for OK or nonzero for error.
*
* This and related APIs operate identically with OpenSSL or mbedTLS backends.
*/
LWS_VISIBLE LWS_EXTERN int
lws_genaes_create(struct lws_genaes_ctx *ctx, enum enum_aes_operation op,
enum enum_aes_modes mode, struct lws_gencrypto_keyelem *el,
enum enum_aes_padding padding, void *engine);
/** lws_genaes_destroy() - Destroy genaes AES context
*
* \param ctx: your struct lws_genaes_ctx
* \param tag: NULL, or, GCM-only: buffer to receive tag
* \param tlen: 0, or, GCM-only: length of tag buffer
*
* Destroys any allocations related to \p ctx.
*
* For GCM only, up to tlen bytes of tag buffer will be set on exit.
*
* This and related APIs operate identically with OpenSSL or mbedTLS backends.
*/
LWS_VISIBLE LWS_EXTERN int
lws_genaes_destroy(struct lws_genaes_ctx *ctx, unsigned char *tag, size_t tlen);
/** lws_genaes_crypt() - Encrypt or decrypt
*
* \param ctx: your struct lws_genaes_ctx
* \param in: input plaintext or ciphertext
* \param len: length of input (which is always length of output)
* \param out: output plaintext or ciphertext
* \param iv_or_nonce_ctr_or_data_unit_16: NULL, iv, nonce_ctr16, or data_unit16
* \param stream_block_16: pointer to 16-byte stream block for CTR mode only
* \param nc_or_iv_off: NULL or pointer to nc, or iv_off
* \param taglen: length of tag
*
* Encrypts or decrypts using the AES mode set when the ctx was created.
* The last three arguments have different meanings depending on the mode:
*
* KW CBC CFB128 CFB8 CTR ECB OFB XTS
* iv_or_nonce_ct.._unit_16 : iv iv iv iv nonce NULL iv dataunt
* stream_block_16 : NULL NULL NULL NULL stream NULL NULL NULL
* nc_or_iv_off : NULL NULL iv_off NULL nc_off NULL iv_off NULL
*
* For GCM:
*
* iv_or_nonce_ctr_or_data_unit_16 : iv
* stream_block_16 : pointer to tag
* nc_or_iv_off : set pointed-to size_t to iv length
* in : first call: additional data, subsequently
* : input data
* len : first call: add data length, subsequently
* : input / output length
*
* The length of the optional arg is always 16 if used, regardless of the mode.
*
* Returns 0 for OK or nonzero for error.
*
* This and related APIs operate identically with OpenSSL or mbedTLS backends.
*/
LWS_VISIBLE LWS_EXTERN int
lws_genaes_crypt(struct lws_genaes_ctx *ctx, const uint8_t *in, size_t len,
uint8_t *out,
uint8_t *iv_or_nonce_ctr_or_data_unit_16,
uint8_t *stream_block_16,
size_t *nc_or_iv_off, int taglen);
///@}
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